Support and organic electroluminescence element comprising the support

ABSTRACT

Disclosed is a support which comprises a flexible substrate and provided thereon, one or two or more polymer layers and one or two or more sealing layers, wherein at least one of the polymer layers and the sealing layers is formed by a process comprising the steps of exciting a reactive gas at a space between opposed electrodes at atmospheric pressure or approximately atmospheric pressure by electric discharge to be in the plasma state, and exposing the flexible substrate, the polymer layer or the sealing layer to the reactive gas in the plasma state.

FIELD OF THE INVENTION

This invention relates to a support with excellent moisture sealingability and without layer exfoliation, which is useful for a display oran electronic device, and an organic electroluminescence elementemploying the support.

BACKGROUND OF THE INVENTION

A glass plate has been used in view of thermal stability ortransparency, as a base plate of a display such as a liquid crystaldisplay or an organic electroluminescence display or as a base plate ofan electronic device such as CCD or a CMOS sensor.

In recent years, as portable information terminal units such as acellular phone spread, use of a plastic substrate, which is flexible,light and difficult to be damaged, has been studied in place for a glasssubstrate, which is heavy or easy to be damaged, in a display or anelectro-optical device provided in the terminal units.

However, since the plastic substrate has a moisture penetrability, it isdifficult to be applied to a device such as an organicelectroluminescence display (hereinafter referred to also as an organicelectroluminescence element) which is damaged by moisture to causedeterioration of its performance. Accordingly, how to seal moisture is aproblem.

In order to overcome the above problem, in WO-0036665 is proposed alayer (hereinafter referred to as proposed prior art) with a highmoisture sealing ability, a composite layer employing silica with a lowmoisture penetrability and an acryl monomer, which is formed bydepositing on a substrate a monomer containing an acryl monomer,polymerizing the deposited monomer, depositing silica, and furtherdepositing a monomer containing an acryl monomer and polymerizing thedeposited monomer. However, in this literature, concrete materials usedor concrete experiment conditions are not disclosed. The presentinventors have traced the proposed prior art, and as a result, they havefound that the proposed prior art has problem in that the formed polymerlayer and inorganic substance layer are likely to exfoliate duringhandling and moisture penetrates in the portions where the layersexfoliate.

SUMMARY OF THE INVENTION

Accordingly, an object of the invention is to provide a support withexcellent moisture sealing ability and without layer exfoliation, whichis useful for a display or an electronic device, and to provide anorganic electroluminescence element with long life employing thesupport.

BRIEF EXPLANATION OF THE DRAWING

FIG. 1 shows one embodiment of a plasma discharge treatment chamber.

FIG. 2( a) and FIG. 2( b) show examples of roll electrode.

FIG. 3( a) and FIG. 3( b) show perspective views of fixed electrode.

FIG. 4 shows a plasma discharge chamber in which the fixed prismaticelectrodes are arranged around the circumference of the roll electrode.

FIG. 5 shows a schematic view of one embodiment of the plasma layerformation apparatus.

FIG. 6 shows a schematic view of another plasma layer formationapparatus.

FIG. 7 shows a sectional view of one embodiment of the support of theinvention.

FIG. 8 shows a sectional view of another embodiment of the support ofthe invention.

FIG. 9 shows a sectional view of one embodiment of the organicelectroluminescence element of the invention.

FIG. 10 shows a schematic view of another embodiment of the organic ELelement of the invention.

FIG. 11 shows a schematic view of still another embodiment of theorganic electroluminescence element of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The object of the invention has been attained by the followingconstitutions:

1-1. A support comprising a flexible substrate and provided thereon, oneor two or more polymer layers and one or two or more sealing layers,wherein at least one of the polymer layers and the sealing layers isformed by a process comprising the steps of exciting a reactive gas at aspace between opposed electrodes at atmospheric pressure orapproximately atmospheric pressure by electric discharge to be in theplasma state, and exposing the flexible substrate, the polymer layer orthe sealing layer to the reactive gas in the plasma state.

1-2. The support of item 1-1 above, wherein the polymer layer contains apolymeric compound, and the sealing layer contains a metal oxide, ametal nitride or a metal oxide nitride.

1-3. The support of item 1-2 above, wherein the polymeric compound isobtained by polymerization of a monomer comprising a vinyl compound oran acetylene compound, the metal oxide is a compound selected fromsilicon oxide, titanium oxide, indium oxide, tin oxide, indium tin oxide(ITO), or alumina, the metal nitride is a compound selected from siliconnitride or titanium nitride, the metal oxide nitride is a compoundselected from silicon oxide nitride, or titanium oxide nitride, and thereactive gas is an organometallic compound or the monomer.

1-4. The support of item 1-3 above, wherein the organometallic compoundis an organosilicon compound, an organotitanium compound, an organotincompound, an organoindium compound, an organoaluminum compound, or acomposite compound thereof.

1-5. The support of item 1-4 above, wherein the organosilicon compoundis a compound represented by formula (1), (2), (3), or (4),

wherein R₂₁, R₂₂, R₂₃, R₂₄, R₂₅, and R₂₆ independently represent ahydrogen atom or a monovalent substituent, and n1 represents a naturalnumber.

wherein R₃₁ and R₃₂ independently represent a hydrogen atom or amonovalent substituent, and n2 represents a natural number.(R₄₁)_(n)Si(R₄₂)_((4-n))  Formula (3)

wherein R₄₁ and R₄₂ independently represent a hydrogen atom or amonovalent substituent, and n represents an integer of from 0 to 3.

wherein A represents a single bond or a divalent group, R₅₁, R₅₂, R₅₃,R₅₄, and R₅₅ independently represent a hydrogen atom, a halogen atom, analkyl group, a cycloalkyl group, an alkenyl group, an aryl group, anaromatic heterocyclic group, an amino group or a cyano group, providedthat R₅₁ and R₅₂, or R₅₄ and R₅₅ may combine with each other to form aring.

1-6. The support of item 1-5 above, wherein the compound represented byformula (4) is a compound represented by formula (5),

wherein R₆₁, R₆₂, R₆₃, R₆₄, R₆₅, and R₆₆ independently represent ahydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, analkenyl group, an aryl group, or an aromatic heterocyclic group.

1-7. The support of item 1-3 above, wherein the content of the metaloxide, the metal nitride and/or the metal oxide nitride in the sealinglayer is not less than 90% by weight.

1-8. The support of claim 1-1 above, wherein the sealing layer containscarbon in an amount of from 0.2 to 5% by weight.

1-9. The support of item 1-1 above, wherein the sealing layer has athickness of from 50 to 2000 nm, and the polymer layer has a thicknessof from 50 to 2000 nm.

1-10. The support of item 1-1 above, wherein at least one of the sealinglayers is formed by a process comprising the steps of exciting areactive gas at a space between opposed electrodes at atmosphericpressure or approximately atmospheric pressure by discharge to be in theplasma state, and exposing the flexible substrate to the reactive gas inthe plasma state.

1-11. The support of item 1-1 above, wherein the sealing layer is formedby a process comprising the steps of exciting a reactive gas at a spacebetween opposed electrodes at atmospheric pressure or approximatelyatmospheric pressure by discharge to be in the plasma state, thedischarge being induced by supply of a power of not less than 1 W/cm²with a frequency exceeding 100 kHz, and exposing the flexible substrateto the reactive gas in the plasma state.

1-12. An organic electroluminescence element comprising a support,wherein the support comprises a flexible substrate and provided thereon,one or two or more polymer layers and one or two or more sealing layers,wherein at least one of the polymer layers and the sealing layers isformed by a process comprising the steps of exciting a reactive gas at aspace between opposed electrodes at atmospheric pressure orapproximately atmospheric pressure by discharge to be in the plasmastate, and exposing the flexible substrate to the reactive gas in theplasma state.

1-13. A support comprising a substrate and provided thereon, at leasttwo layers containing a metal oxide, a metal nitride or a metal nitrideoxide, the two layers being different in carbon concentration, whereinat least one of the layers is formed by a process comprising the stepsof exciting a reactive gas at a space between opposed electrodes atatmospheric pressure or approximately atmospheric pressure by electricdischarge to be in the plasma state, and exposing the substrate or thelayer to the reactive gas in the plasma state.

2-1. A support comprising a flexible substrate and provided thereon, apolymer layer and a sealing layer, wherein at least one of the polymerlayer and the sealing layer, is a layer formed by exciting a reactivegas at a space between opposed electrodes at atmospheric pressure orapproximately atmospheric pressure by discharge to be in the plasmastate, and exposing the flexible substrate to the reactive gas in theplasma state.

2-2. The support of item 2-1 above, wherein the polymer layer contains apolymeric compound, and the sealing layer contains a metal oxide, ametal nitride, or a metal oxide nitride.

2-3. The support of item 2-1 or 2-2 above, wherein the sealing layer isformed by discharge induced by supply of a power of not less than 1W/cm² with a frequency exceeding 100 kHz.

2-4. An organic electroluminescence element comprising the support ofany one of items 2-1 through 2-3.

The present inventors have made an extensive study, and as a result,they have developed a support having the constitution described above,which overcomes the above problem, and also developed an organicelectroluminescence element (hereinafter referred to also as organic ELelement) with a long life employing the support.

As described above, in recent years, use of a plastic substrate, whichis flexible, light and difficult to be damaged, has been studied toreplace a glass substrate, which is heavy or easy to be damaged, incrystal liquid or EL displays or electro-optical devices.

However, plastic substrates currently manufactured have relatively highmoisture penetrability and contain some moisture. Therefore, the plasticsubstrates, when used in an organic electroluminescence display, haveproblem in that the moisture gradually diffuses in the display, and thediffused moisture lowers durability of the display.

In order to overcome the above problem, attempts have been made toobtain a support applicable to various electronic devices in which aplastic sheet is subjected to a certain treatment to minimize moisturepenetrability or to reduce the moisture content. For example, in view ofthe above proposed prior art, an attempt has been made in which a thinlayer of silica or glass with low moisture penetrability is formed on aplastic substrate to obtain a composite material. However, the thinlayer has defects, and a specific layer thickness not less than acertain value is necessary to lower moisture penetrability and seal anymoisture in the support.

When a layer containing silica or containing an inorganic material withlow moisture penetrability such as a metal oxide, a metal nitride or ametal oxide nitride (in an amount of at least 90% by weight) is formedon a plastic substrate with a thickness sufficient to minimize moisturepenetrability to obtain a support, the resulting support losesflexibility of the plastic substrate capable of being folded and causeslayer exfoliation, which lowers moisture sealing ability.

Provision on a substrate of plural layers, not a single layer, helps torestrain layer exfoliation to some degree, which needs an extra processand increases manufacturing cost. Further, since it is essential tocontrol physical properties of each layer, the plural layers are notnecessarily preferable.

The invention is a support comprising a flexible substrate and providedthereon, a polymer layer and a sealing layer, wherein at least one ofthe polymer layer and the sealing layer, is a layer formed by exciting areactive gas at a space between opposed electrodes at atmosphericpressure or approximately atmospheric pressure by discharge to be in theplasma state, and exposing the flexible substrate to the reactive gas inthe plasma state. The present inventors have found that the supportdescribed above is a support with low moisture penetrability, reduceddeterioration due to fold, and excellent moisture sealing ability andwithout layer exfoliation, and they have completed this invention.

The support of the invention is a support comprising a flexiblesubstrate and provided thereon, a polymer layer and a sealing layer,wherein at least one of the polymer layer and the sealing layer is alayer formed according to plasma treating of the flexible substrate atatmospheric pressure or approximately atmospheric pressure, andpreferably a support comprising a flexible substrate and providedthereon, a polymer layer and a sealing layer, wherein at least one ofthe sealing layers is a layer formed according to plasma treatment ofthe flexible substrate at atmospheric pressure or approximatelyatmospheric pressure. It is also preferred that the polymer layer is alayer formed according to plasma treatment of the flexible substrate atatmospheric pressure or approximately atmospheric pressure.

The sealing layer used in the invention will be explained below.

A metal oxide, a metal nitride and a metal oxide nitride are suitablefor a material with low moisture penetrability. These form a relativelyhard layer with high density.

A sealing layer comprising a metal oxide, a metal nitride or a metaloxide nitride can be obtained according to a method carrying out plasmatreatment at atmospheric pressure or approximately atmospheric pressure,that is, an atmospheric pressure plasma method which comprises excitinga reactive gas, an organometallic compound between opposed electrodes tobe in a plasma state, and exposing a substrate to the reactive gas inthe plasma state to form the sealing layer on the substrate. Herein,atmospheric pressure or approximately atmospheric pressure hereinreferred to implies approximately atmospheric pressure, and typically apressure of 20 kPa to 110 kPa, and preferably 93 kPa to 104 kPa.

The reactive gas used in the atmospheric pressure plasma method ispreferably an organometallic compound. Flexibility of the sealing layercan be controlled by employing the organometallic compound as a reactivegas and by adjusting the plasma generation conditions. The carboncontent of the sealing layer can be controlled adjusting the plasmageneration conditions. Flexibility of the sealing layer varies dependingon the carbon content of the layer.

Since particles such as ions from the reactive gas used are presentbetween the opposed electrodes at a high concentration in theatmospheric plasma method, carbon derived from the organometalliccompound used is likely to remain in the formed layer. A slight amountof carbon is preferably contained in the layer to provide flexibility tothe layer and increase abrasion resistance of the layer. The carboncontent of the layer is preferably from 0.2 to 5% by weight. When thecarbon content exceeds 5% by weight, layer properties such as refractiveindex may change with time, which is not desirable.

In order to obtain a layer with a carbon content of from 0.2 to 5% byweight, discharge is preferably induced supplying a power of not lessthan 1 W/cm² with a frequency exceeding 100 kHz. Further, the waveformof a high frequency voltage applied is preferably a continuous sinewave.

The carbon content of the layer depends mainly on the frequency andpower supplied from a power source, and decreases as frequency ofvoltage applied to electrodes is raised or power supplied is increased.When a hydrogen gas is incorporated in the mixed gas used, carbon atomsare likely to be consumed, and the carbon content can be controlledthereby also.

A sealing layer will be explained below, which is formed according to aplasma method carried out at atmospheric pressure or approximatelyatmospheric pressure, employing an organometallic compound as thereactive gas.

The substrate used in the invention may be any as long as it isflexible. The flexible substrate may be comprised of a single sheet,plural sheets or a sheet whose surface is subjected to subbingtreatment. The flexible substrate preferably used is a resin substrate.Examples of the substrate include a polyester film such as apolyethylene terephthalate or polyethylene naphthalate film, apolyethylene film, a polypropylene film, a cellophane film, a film of acellulose ester such as cellulose diacetate, cellulose triacetate,cellulose acetate butyrate, cellulose acetate propionate, celluloseacetate phthalate, cellulose nitrate or their derivative, apolyvinylidene chloride film, a polyvinyl alcohol film, anethylene-vinyl alcohol film, a syndiotactic polystyrene film, apolycarbonate film, a norbornene resin film, a polymethylpentene film, apolyetherketone film, a polyimide film, a polyethersulfone film, apolysulfone film, a polyetherketoneimide film, a polyamide film, afluorine-containing resin film, a nylon film, a polymethyl methacrylatefilm, an acryl film, and a polyarylate film. A cyclopolyolefin resinsuch as ARTON (produced by JSR Co., Ltd.) or APEL produced by MitsuiKagaku Co., Ltd.) can be preferably used. The thickness of the substrateis preferably from 30 μm to 1 cm, and more preferably from 50 μm to 1000μm.

The layer containing the metal oxide, metal nitride or metal oxidenitride described above as a main component refers to a layer containingthe metal oxide, metal nitride or metal oxide nitride in an amount ofnot less than 50% by weight.

Examples of the metal oxide include silicon oxide, titanium oxide,indium oxide, tin oxide, indium tin oxide (ITO), and alumina. Examplesof the metal nitride include titanium nitride and silicon nitride.Examples of the metal oxide nitride include silicon oxide nitride, andtitanium oxide nitride.

The silicon oxide is highly transparent, but has a poor gas barrierproperty and a moisture penetrating property. It is preferred that thesilicon oxide layer preferably contains a nitrogen atom. The siliconoxide nitride and titanium oxide nitride are represented by SiOxNy andTiOxNy, respectively. When the nitrogen content in a layer is increased,the gas barrier property is enhanced, but light transmittance islowered. When high light transmittance is necessary for the support, xand y preferably satisfy the following relationship:0.4≦x/(x+y)≦0.8

The oxygen atom or nitrogen atom content can be measured employing XPS(ESCA LAB-200R produced by VIEWING ANGLE Scientific Co., Ltd. in thesame manner as a carbon atom content described later.

In the invention, the main component of the sealing layer is preferablyan oxide of aluminum, silicon, or titanium or an oxide nitride ofsilicon, or titanium, in view of low moisture penetrability. In theinvention, when plural layers containing a metal oxide, a metal oxidenitride or a metal nitride are formed, at least one of the layers has acarbon content of from 1 to 40 atomic %. When plural layers containing ametal oxide, a metal oxide nitride or a metal nitride are formed, theplural layers are preferably those containing the same metal oxide, thesame metal oxide nitride, or the same metal nitride but having adifferent carbon content.

As the organotin compound, organosilicon compound or organotitaniumcompound described above, a metal hydride compound or a metal alkoxidecompound is preferably used in view of handling, and the metal alkoxidecompound is more preferably used, since it is not corrosive, andgenerates no harmful gas nor causes contamination. When the organotincompound, organosilicon compound or organotitanium compound describedabove is introduced into a discharge space or a space between theelectrodes. As the reactive gas for forming the sealing layer, anorganometallic compound and a metal hydride compound can be used. Thecompounds may be in the form of gas, liquid, or solid at ordinarytemperature and ordinary pressure. When they are gas at ordinarytemperature and ordinary pressure, they can be introduced in thedischarge space as they are. When they are liquid or solid, they aregasified by heating, or under reduced pressure or ultrasonic waveradiation, and used. The above compound may be diluted with anothersolvent. The solvents include an organic solvent such as methanol,ethanol, n-hexane or a mixture thereof. Since these solvents aredecomposed during discharge plasma treatment, their influence on thelayer formed on the substrate can be neglected.

A compound represented by formulae (1) through (4) described below ispreferred as the organometallic compound for forming a silicon oxidelayer, since it is not corrosive, and generates no harmful gas norcauses contamination.

wherein R₂₁ through R₂₆ independently represent a hydrogen atom or amonovalent substituent, and n1 represents a natural number.

Examples of the compound represented by formula (1) includehexamethyldisiloxane (HMDSO), tetramethyldisiloxane (TMDSO), and1,1,3,3,5,5-hexamethyltrisiloxane.

wherein R₃₁ and R₃₂ independently represent a hydrogen atom or amonovalent substituent, and n2 represents a natural number.

Examples of the compound represented by formula (2) includehexamethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, anddecamethylcyclopentanesiloxane.(R₄₁)nSi(R₄₂)4-n  Formula (3)

wherein R₄₁ and R₄₂ independently represent a hydrogen atom or amonovalent substituent, and n represents an integer of from 0 to 3.

Examples of the organic compound represented by formula (3) includetetraethoxysilane (TEOS), methyltrimethoxysilane, methyltriethoxysilane,dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylethoxysilane,ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane,n-propyltriethoxysilane, n-butyltrimethoxysilane,i-butyltrimethoxysilane, n-hexyltrimethoxysilane,phenyltrimethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane.

wherein A represents a single bond or a divalent group, R₅₁ through R₅₅independently represent a hydrogen atom, a halogen atom, an alkyl group,a cycloalkyl group, an alkenyl group, an aryl group, an aromaticheterocyclic group, an amino group or a cyano group, provided that R₅₁and R₅₂ or R₅₄ and R₅₅ may combine with each other to form a ring.

In formula (4), A is preferably a single bond or a divalent group havinga carbon atom number of 1 to 3. R₅₄ and R₅₅ may combine with each otherto form a ring, and examples of the formed ring include a pyrrole ring,a piperidine ring, a piperazine ring, and an imidazole ring. It ispreferred that R₅₁ through R₅₃ independently represent a hydrogen atom,a methyl group or an amino group.

Examples of the organic compound represented by formula (4) includeaminomethyltrimethylsilane, dimethyldimethylaminosilane,dimethylaminotrimethylsilane, allylaminotrimethylsilane,diethylaminodimethylsilane, 1-trimethylsilylpyrrole,1-trimethylsilylpyrrolidine, isopropylaminomethyltrimethylsilane,diethylaminotrimethylsilane, anilinotrimethylsilane,2-piperidinoethyltrimethylsilane, 3-butylaminopropyltrimethylsilane,3-piperidinopropyltrimethylsilane, bis(dimethylamino)methylsilane,1-trimethylsilylimidazole, bis(ethylamino)dimethylsilane,bis(butylamino)dimethylsilane,2-aminoethylaminomethyldimethylphenylsilane,3-(4-methylpiperazinopropyl) trimethylsilane,dimethylphenylpiperazinomethylsilane,butyldimethyl-3-piperazinopropylsilane, dianilinodimethylsilane, andbis(dimethylamino)diphenylsilane.

A compound represented by formula (4) is preferably a compoundrepresented by formula (5).

wherein R₆₁ through R₆₆ independently represent a hydrogen atom, ahalogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, anaryl group, or an aromatic heterocyclic group.

In formula (5), it is preferred that R₆₁ through R₆₆ independentlyrepresent a hydrocarbon group having a carbon atom number of 1 through10, in view of easy gasification, and it is more preferred that at leasttwo of R₆₁ through R₆₃ are methyl groups and at least two of R₆₄ throughR₆₆ are methyl groups.

Examples of the organic compound represented by formula (5) include1,1,3,3-tetramethyldisilazane,1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisilazane,hexamethyldisilazane, and 1,3-divinyl-1,1,3,3-tetramethyldisilazane.

In order to form a tin oxide layer, for example, dibutyltin diacetate isused. Further, in order to form an aluminum oxide layer, for example,aluminum isopropoxide or tris(2,4-pentadionato)aluminum is used. Inorder to form a titanium oxide layer, for example, titaniumtetraisopropoxide is used.

Employing a mixed gas of an oxygen gas or a nitrogen gas in a specificamount and the above organometallic compound, a layer containing a metalatom such as silicon or tin and at least one of a nitrogen atom and anoxygen atom.

In order to adjust a carbon content of the formed layer, a hydrogen gasmay be further mixed in the mixed gas described above. A mixed gas inwhich inert gas belonging to a group XVIII of periodic table such ashelium, neon, argon, krypton, xenon, or radon, preferably helium orargon, is mixed in the reactive gas is introduced in the atmosphericpressure plasma discharge generating apparatus (plasma generatingapparatus) to form a layer. The content ratio of the inert gas to thereactive gas in the mixed gas used is 90.0 to 99.9% by volume, althoughit differs due to properties of a layer formed.

The above-described mixed gas for forming a layer containing a specificamount of for example, Si, O, N, and C will be explained below.

Explanation will be made regarding a silicon oxide nitride layer to havebeen formed employing a mixed gas of silazane and oxygen gas, in whichx/(x+y) is not more than 0.8, and contains carbon in an amount of forexample, 0.2 to 5% by weight. In this case, The Si and N in the layer isderived from silazane.

The oxygen gas content of the mixed gas is preferably from 0.01 to 5% byvolume, and more preferably from 0.05 to 1% by volume. Consideringreaction efficiency of oxygen gas and silazane, the content ratio (bymole) of oxygen gas to silazane in the mixed gas is set so that it is 1to 4 times the content ratio in the layer formed. Thus, the oxygen gascontent and the content ratio of the oxygen gas to the silazane aredetermined.

In forming a Si and N containing layer from silazane without usingoxygen, the content of gasified silazane in the mixed gas may be from0.2 to 1.5% by volume. Since a considerable amount of carbon remains inthe layer, a part of the carbon is removed, employing a mixed gascontaining a hydrogen gas in an amount of at most 2% by volume.

Besides the organosilicon compound, an inorganic silicon compound can bealso used as the Si providing source.

As the oxygen providing source, ozone, carbon dioxide, or water (steam)may be used, besides an oxygen gas. As the nitrogen providing source,ammonia or nitrogen oxides may be used, besides silazane or a nitrogengas.

The plasma layer formation apparatus used in the formation of the layerin the invention will be explained employing FIGS. 1 to 6. In thefigures, a substrate F is a long-length film used as one example of asubstrate.

In the invention, the discharge plasma treatment preferably used iscarried out at atmospheric pressure or at approximately atmosphericpressure. Herein, approximately atmospheric pressure herein referred toimplies a pressure of 20 kPa to 110 kPa, and preferably 93 kPa to 104kPa.

FIG. 1 shows one embodiment of a plasma discharge treatment chamber inthe plasma layer formation apparatus. In the plasma discharge treatmentchamber 10 of FIG. 1, substrate F in the film form is transported whilewound around roll electrode 25 rotating in the transport direction(clockwise in FIG. 1). Plural fixed electrodes 26, which are fixedaround roll electrode 25, are in the form of cylinder and opposed to theroll electrode 25.

The plasma discharge vessel 11, constituting the plasma dischargetreatment chamber 10, is preferably a vessel of pyrex (R) glass, but avessel of metal may be used if insulation from the electrodes issecured. For example, the vessel may be a vessel of aluminum orstainless steel laminated with a polyimide resin or a vessel of themetal which is thermally sprayed with ceramic to form an insulationlayer on the surface.

The substrate F, which has been wound around the roll electrode 25, ispressed with nip rollers 15 and 16, transported into a discharge spacein the plasma discharge vessel 11 through guide roller 24, subjected todischarge plasma treatment, and then transported into the next processthrough guide roller 27. Since discharge treatment in the invention canbe carried out at atmospheric pressure or approximately atmosphericpressure but not under vacuum condition, continuous treatment asdescribed above is possible, which can provide high productiveefficiency.

Blade 14 is provided at the vicinity of the nip rollers 15 and 16, andprevents air accompanying the transported substrate F from entering theplasma discharge vessel 11. The volume of the accompanying air ispreferably not more than 1% by volume and more preferably not more than0.1% by volume, based on the total volume of air in the plasma dischargevessel 11, which can be attained by the nip rollers 15 and 16 above.

A mixed gas used in the discharge plasma treatment is introduced intothe plasma discharge vessel 11 from supply port 12, and exhausted fromexhaust port 13 after discharge treatment.

Roll electrode 25 is a ground electrode, and opposed to voltageapplication electrodes, plural fixed electrodes 26. Discharge is inducedat a space between the roll electrode and the fixed electrodes, thereactive gas supplied to the space is excited by the discharge to be inthe state of plasma, and a long length substrate transported onto theroll electrode 25 is exposed to the reactive gas in the plasma state toform a layer resulting from the reactive gas on the substrate.

It is preferred that a layer formation rate be increased by high plasmadensity between the opposed electrodes, and high electric power with ahigh frequency be supplied in order to control the carbon content of thelayer formed. Typically, a high frequency voltage with a frequency offrom 100 kHz to 150 MHz and preferably not less than 200 kHz ispreferably supplied. The power supplied across the space between theopposed electrodes is preferably from 1 to 50 W/cm², and more preferablynot less than 2 W/cm².

The electrode surface area (cm²) to which voltage is applied refers tothe surface area of the electrode at which discharge occurs.

The high frequency voltage applied to the electrodes may be a continuoussine wave or a discontinuous pulsed wave. The sine wave is preferred inproviding high layer formation speed.

Such electrodes are preferably those in which a dielectric is coated onthe surface of a metal base material. A dielectric is coated on at leastone of fixed electrodes 26 and a roll electrode 25 opposed to eachother, and preferably on both electrodes. The dielectric is preferablyan inorganic compound having a dielectric constant of from 6 to 45.

When one of the electrodes 25 and 26 has a dielectric layer, the minimumspace distance between the electrode and the dielectric layer ispreferably from 0.5 to 20 mm, and more preferably in the range of 1mm±0.5 mm, and when both electrodes described above have a dielectriclayer, the minimum space distance between both dielectric layers ispreferably from 0.5 to 20 mm, and more preferably in the range of 1mm±0.5 mm, in carrying out uniform discharge. The space distance betweenthe opposed electrodes is determined considering thickness of adielectric layer provided on the conductive metal base material, orapplied voltage level.

When a flexible substrate placed or transported between the electrodesis exposed to plasma, employing as one of the electrodes a rollelectrode capable of transporting the substrate while directlycontacting the roll electrode and surface-finishing the dielectric layerof the dielectric coated electrode by polishing treatment so as toobtain a surface roughness Rmax (according to JIS B 0601) of not morethan 10 μm, the dielectric layer thickness or the gap between theelectrodes can be maintained constant, and stable discharge can becarried out. Further, coverage of non-porous inorganic dielectric layerwith high precision and without strain or cracks due to thermalshrinkage difference or residual stress can provide an electrode withgreatly increased durability.

In preparing a dielectric coated electrode by coating a dielectric layeron a metal base material, it is necessary that the dielectric layersurface be surface finished by polishing treatment as described aboveand the difference in thermal expansion between the dielectric layer andthe metal base material be reduced. Accordingly, a metal base materialis preferably lined with an inorganic material layer, in which the foamcontent is controlled, as a stress absorbing layer. The inorganicmaterial for lining is preferably glass produced according to a meltingmethod, which is known as enamel etc. It is preferred that the foamcontent of the lowest layer which contacts the conductive metal basematerial is 20 to 30% by volume, and the foam content of the layer orlayers provided on the lowest layer is not more than 5% by volume, whichprovides a good electrode with high density and without cracks.

Another preferred method for coating a dielectric on a metal basematerial is a method in which a ceramic is thermally splayed on themetal base material to form a ceramic layer with a void content of notmore than 10% by volume, and sealed with an inorganic material capableof being hardened by a sol-gel reaction. In order to accelerate the solgel reaction, heat hardening or UV irradiation is preferably carriedout. Sealing treatment, in which coating of diluted sealing solution andhardening are alternately repeated several times, provides an electrodewith improved inorganic property, with high density and without anydeterioration.

FIG. 2( a) and FIG. 2( b) show roll electrode 25 c and roll electrode25C, respectively, as examples of roll electrode 25.

As is shown in FIG. 2( a), roll electrode 25 c, which is a groundelectrode, is an electrode in which a conductive base roll 25 a such asa metal roll is coated with ceramic to form a ceramic dielectric layer25 b as a dielectric layer, the coating being carried out by thermallyspraying ceramic on the base roll to form a ceramic layer, and sealingthe ceramic layer with sealing materials such as inorganic compounds.The roll electrode is prepared to have a ceramic dielectric layer with athickness of 1 mm and a roll diameter of 200φ, and is grounded. Theceramic material used for thermal spraying is preferably alumina,silicon nitride, and more preferably alumina in view of easyprocessability.

Further, as is shown in the roll electrode 25C of FIG. 2( b), the rollelectrode may be an electrode in which a conductive base roll 25A suchas a metal roll is lining coated with inorganic materials to form alined dielectric layer 25B as a dielectric layer. Materials for liningare preferably silicate glass, borate glass, phosphate glass, germanateglass, tellurite glass, aluminate glass, and vanadate glass. Amongthese, borate glass is more preferably used in view of easyprocessability.

Examples of a metal used in the conductive metal base roll 25 a or 25Ainclude metals such as silver, platinum, stainless steel, aluminum, andiron. Stainless steel is preferable in view of processability.

In one embodiment carried out in the invention, a base roll for the rollelectrode employs a stainless steel jacket roll having therein a coolingmeans (not illustrated in the Figs.) employing chilled water.

The roll electrodes 25 c and 25C (similarly, roll electrode 25) are setto rotate around the axes 25 d and 25D, respectively, by a drivingsystem not illustrated.

FIG. 3( a) shows a perspective view of fixed electrode 26. The fixedelectrode is not limited to a cylindrical form, an may be in theprismatic form as shown in fixed electrode 36 of FIG. 3( b). Theprismatic electrode has a discharge area larger than the cylindricalelectrode 26, and is preferably used according to properties of thelayer formed.

The fixed electrodes 26 and 36 have the same constitution as that of theroll electrode 25 c or 25C described above. That is, in the same manneras in roll electrode 25 (25 c and 25C) above, dielectric layers 26 b and36 b are coated on hollow stainless steel pipes 26 a and 36 a,respectively, and the resulting electrodes are constructed so as to becooled with chilled water during discharge. The dielectric layers 26 band 36 b may be a layer formed by ceramic thermal spraying or a layerformed by lining.

In an example as shown in FIG. 1, fixed electrodes having a dielectriclayer are prepared to give a roll diameter of 12φ or 15φ, and fourteenof the fixed electrodes are arranged around the circumference of theroll electrode described above.

FIG. 4 shows a plasma discharge chamber 30 in which the fixed prismaticelectrode 36 as shown in FIG. 3( b) is arranged around the circumferenceof the roll electrode 25. The numerical numbers shown in FIG. 4 mean thesame as denoted in FIG. 1.

FIG. 5 shows a schematic view of one embodiment of the plasma layerformation apparatus used in the invention. In FIG. 5, the plasma layerformation apparatus 50 is equipped with plasma discharge chamber 30shown in FIG. 4. In the plasma layer formation apparatus 50, a gasgenerating device 51, a power source 41, and an electrode cooling device55 and so on are further provided in addition to plasma dischargechamber 30. The electrode cooling device 55 is comprised of a tank 57containing a cooling agent and a pump 56. As the cooling agent,insulating materials such as distilled water and oil are used. The gapdistance between the opposed electrodes in the plasma discharge chamber30 shown in FIG. 5 is, for example, approximately 1 mm.

A mixed gas generated in the gas generating device 51 is introduced fromsupply port 12 in a controlled amount into the plasma discharge chamber30, in which roll electrode 25 and fixed electrode 36 are arranged at apredetermined position, whereby the plasma discharge vessel 11 ischarged with the mixed gas, and thereafter, the unnecessary gas isexhausted from the exhaust port 13.

Subsequently, the roll electrode 25 being grounded, voltage is appliedto electrodes 36 by power source 41 to generate discharge plasma. Aflexible substrate F is supplied from stock roll FF through rolls 54,and transported to a gap between the electrodes in the plasma dischargechamber 30 through guide roller 24 so that the one side of the substratecontacts the surface of the roll electrode 25. During transporting, theflexible substrate F is subjected to discharge plasma treatment, andthen transported to the next processing through guide roller 27. In theabove, only the surface of the flexible substrate F opposite the surfacecontacting the roll electrode is subjected to discharge treatment.

In order to minimize an adverse effect due to high temperature duringthe discharge plasma treatment, the substrate temperature is cooled to atemperature of preferably from ordinary temperature (15 to 25° C.) toless than 200° C., and more preferably from ordinary temperature to 100°C., optionally employing an electrode cooling means 55. Numericalnumbers 14, 15 and 16 mean the same as in FIG. 1.

FIG. 6 shows a schematic view of a plasma layer formation apparatus 60used in the invention. The plasma layer formation apparatus 60 is usedwhen a layer is formed on a substrate which cannot be provided at thespace between the opposed electrodes, for example, a substrate 61 havinga great thickness, wherein a reactive gas to have been in a plasma stateis jetted onto the substrate to form a layer on the substrate.

In the plasma layer formation apparatus 60 of FIG. 6, numerical numbers35 a, 35 b and 65 represents a dielectric layer, a metal base material,and a power source, respectively. A mixed gas comprised of a reactivegas and inert gas is introduced into a slit formed between the opposedelectrodes in which a dielectric layer 35 a is coated with a metal basematerial 35 b. The introduced reactive gas is excited to a plasma stateby applying voltage to the electrodes, and the gas in the plasma stateis jetted onto the substrate 61 to form a layer on the substrate 61.

Power source 41 of FIG. 5 or power source 65 of FIG. 6, which is usedfor forming the layer in the invention, is not specifically limited. Asthe power sources, impulse high frequency power source (continuous mode,100 kHz) produced by Heiden Kenkyusho, a high frequency power source(200 kHz) produced by Pearl Kogyo Co., Ltd., a high frequency powersource (800 kHz) produced by Pearl Kogyo Co., Ltd., a high frequencypower source (13.56 MHz) produced by Nippon Denshi Co., Ltd., and a highfrequency power source (150 MHz) produced by Pearl Kogyo Co., Ltd. canbe used.

The sealing layer and/or polymer layer in the invention can be formedaccording to the atmospheric pressure plasma method, employing theplasma layer formation apparatus as described above.

The polymer layer contains a polymeric compound as a main component. Thepolymeric compound is obtained by polymerization of a monomer comprisinga vinyl compound or an acetylene compound. When the polymer layer in theinvention is formed according to the atmospheric pressure plasma method,a vinyl compound having a vinyl group or an acetylene compound having anacetylenyl group is preferably used as a reactive gas. Examples of thevinyl compound having a vinyl group or the acetylene compound acetylenylgroup include methyl methacrylate, ethyl acrylate, vinyl acetate,styrene, iso-propyl vinyl ether, and acetylene. When the polymer layeris formed, these compounds can be plasma treated under layer formationconditions such that they are polymerized without being decomposed. Thefrequency of the power source is preferably from 3 to 150 MHz.

The thickness of the sealing layer in the invention can be adjusted,increasing the plasma treatment time, or repeating plasma treatment. Thelayer thickness capable of substantially preventing moisture frompenetrating in the layer is preferably not less than 50 nm, and morepreferably not less than 100 nm. The thick sealing layer provides anexcellent moisture resistance, but since a too thick sealing layer showslow stress relaxation, the thickness thereof is preferably not more than2000 nm. When plural sealing layers are formed, it is preferred thateach sealing layer have the thickness range defined above.

The thickness of the polymer layer in the invention is preferably from50 to 2000 nm, and more preferably from 100 to 1000 nm, in that thesealing layer does not peel from the substrate or has good stressrelaxation. When plural polymer layers are formed, it is preferred thateach polymer layer have the thickness range defined above.

The support of the invention comprising the sealing layer and thepolymer layer will be explained below.

The support of the invention comprises a resin substrate, and providedthereon, a sealing layer having a thickness of preferably not less than100 nm, and more preferably not less than 200 nm, and a polymer layeradjacent to the sealing layer in that order. When the support is folded,the sealing layer is likely to peel off from the substrate, however,stress relaxation of the polymer layer prevents the sealing layer frompeeling off. Further, the polymer layer can provide low moisturepenetration.

FIG. 7 shows a sectional view of the support comprising the layerstructure described above. The support has a resin substrate 100, andprovided thereon, a sealing layer 101 and a polymer layer 102 in thatorder, the polymer layer being adjacent to the sealing layer. Thethickness of both layers may be the same or different.

The preferred embodiment of the invention is a support in which thepolymer layer 102 are provided closer to the substrate 100 than thesealing layer 101, wherein the polymer layer substantially preventsmoisture from penetrating into the layer, and increases adhesion of thesealing layer 101, which provides a moisture sealing property to thesupport, to the substrate.

FIG. 8 shows a sectional view of one embodiment of the support havingtwo or more of the layer structure described above. The support has aresin substrate 100, and provided thereon, a sealing layer 101, apolymer layer 102, a sealing layer 101, and a polymer layer 102 in thatorder. The two sealing layers 101 and the two polymer layers 102 neednot have the same composition or the same layer thickness, respectively.In order to obtain the support having such plural layer structuresaccording to the atmospheric plasma method, the substrate can be plasmatreated in the plasma layer formation apparatus described above severaltimes.

The support of the invention, even when a resin substrate is used as aflexible substrate, can not only maintain the flexibility which theflexible resin has, but can seal moisture contained in the resinsubstrate or water vapor penetrating in the resin substrate due to awater sealing property which the sealing layer has. Accordingly, sincethe sealed inner space of the display can maintain the humidity to below, a flexible display prepared by forming an organicelectroluminescence (EL) element on such a support and sealing it with aflexible material such as a film, preferably the same support as above,can solve problem that properties of the organic electroluminescenceelement which is sensitive to moisture gradually degrade due to themoisture contained in a sealing agent or the support, which greatlylengthen its life.

In the invention, at least one of laminated layers comprising a polymerlayer and a sealing layer is formed by an atmospheric pressure plasmamethod. The layer formation methods in the invention include a method inwhich all the layers are formed by an atmospheric pressure plasmamethod, and a method in which the sealing layer is formed by anatmospheric pressure plasma method, and a polymer layer is formed by avacuum deposition method or other layer formation methods.

The other layer formation methods above are may be any methods includinga sol gel method in which a coating solution is coated, a vacuumdeposition method, a sputtering method, and a CVD method (chemicaldeposition).

The organic electroluminescence element of the invention, employing thesupport of the invention, will be detailed below.

In the invention, the organic electroluminescence element has astructure in which a light emission layer is provided between a pair ofelectrodes, an anode and a cathode. The light emission layer hereinbroadly refers to a layer emitting light when electric current issupplied to the electrode comprised of the cathode and the anode.Typically, the light emission layer is a layer containing an organiccompound emitting light when electric current is supplied to anelectrode comprised of a cathode and an anode.

The organic EL element of the invention has a structure in which a holeinjecting layer, an electron injecting layer, a hole transporting layer,and an electron transporting layer, in addition to the light emissionlayer, are optionally provided between the cathode and the anode.Further, the organic EL element may have a protective layer.

In concrete, the following structures are included.

-   -   (i) Anode/Light emission layer/Cathode    -   (ii) Anode/Hole injecting layer/Light emission layer/Cathode    -   (iii) Anode/Light emission layer/Electron injecting        layer/Cathode    -   (iv) Anode/Hole injecting layer/Light emission layer/Electron        injecting layer/Cathode    -   (v) Anode/Hole injecting layer/Hole transporting layer/Light        emission layer/Electron transporting layer/Electron injecting        layer/Cathode

Further, a cathode buffering layer (for example, a lithium fluoridelayer) may be inserted between the electron injecting layer and thecathode, and an anode buffering layer (for example, a copperphthalocyanine layer) may be inserted between the hole injecting layerand the anode.

The light emission layer may comprise a hole injecting layer, anelectron injecting layer, a hole transporting layer, or an electrontransporting layer. That is, the light emission layer may have at leastone of the following functions: (1) an injecting function capable ofinjecting holes from an anode or a hole injecting layer and injectingelectrons from a cathode or an electron injecting layer by applicationof electric field, (2) a transporting function capable of transportingthe injected charges (holes and electrons) by application of electricfield, and (3) an emission function capable of providing the field ofrecombination of holes and electrons which leads to light emission. Inthe above case, apart from the light emission layer, at least one of thehole injecting layer, the electron injecting layer, the holetransporting layer, and the electron transporting layer is notnecessary. Further, a hole injecting layer, an electron injecting layer,a hole transporting layer, and an electron transporting layer beingadded with a light emission compound, they may be given a function of alight emission layer. In the light emission layer, ease with which holesare injected may be different from ease with which electrons areinjected, and a hole or electron transporting ability represented by itsmobility may be different. However, it is preferred that the lightemission layer has a function of transporting at least one of the holesand electrons.

Light emission materials used in the light emission layer are notspecifically limited, and known materials used in the conventionalorganic EL element can be used. Such a light emission material is mainlyan organic compound, and examples of the organic compound includecompounds disclosed on pages 17 through 26 in “Macromol. Symp.”, vol.125, according to desired color tones.

The light emission materials may have a hole injecting function or aelectron injecting function, in addition to the light emission function.Most of hole injecting materials or electron injecting materials can bealso used as the light emission materials.

The light emission materials may be a polymer such asp-polyphenylenevinylene or polyfluorene, and a polymer in which theabove light emission material is incorporated in the polymer side chainor in the polymer main chain.

The light emission layer may contain a dopant (a guest substance), andas the dopant can be used a compound selected from the known dopantsused in the conventional El element.

Examples of the dopant include quinacridone, DCM, coumarin derivatives,rubrene, decacyclene, pyrazoline derivatives, squalirium derivatives andeuropium complexes. Further, examples of the dopant include iridiumcomplexes (for example, those disclosed in Japanese Patent O.P.I.Publication No. 2001-248759 or compounds represented by formulas onpages 16 through 18 of WO 0070655, for example,tris(2-phenylpyridine)iridium etc.), osmium complexes or platinumcomplexes, for example, 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrinplatinum complex.

As methods of forming a light emission layer employing the compoundsmentioned above, there are known methods for forming a thin layer suchas a deposition method, a spin-coat method, a casting method and an LBmethod. The light emission layer is preferably a molecular depositlayer. The molecular deposit layer herein refers to a layer formed bydeposition of the above compounds in a gaseous state, or bysolidification of the above compounds in a melted state or a liquefiedstate. The molecular deposit layer is distinguished from a thin layer(molecular cumulation layer) formed by an LB method in structure, forexample, an aggregated structure or a higher order structure, or infunction. The function difference results from the structural differencebetween them.

Further, the light emission layer can be formed by the method such asthat described in Japanese Patent O.P.I. Publication No. 57-51781, inwhich the above light emission material is dissolved in a solventtogether with a binder such as a resin, and the thus obtained solutionis coated on a base to form a thin layer by a method such as a spin-coatmethod. The thickness of the thus formed light emission layer is notspecially limited, and is optionally selected, but the thickness isordinarily within the range of from 5 nm to 5 μm.

The hole injecting material for the hole injecting layer may be eitheran organic substance or an inorganic substance as long as it has a holeinjecting ability or an ability to form a barrier to electron. Examplesof the hole injecting material include a triazole derivative, anoxadiazole derivative, an imidazole derivative, a polyarylalkanederivative, a pyrazoline derivative and a pyrazolone derivative, aphenylenediamine derivative, an arylamine derivative, an aminosubstituted chalcone derivative, an oxazole derivative, a styrylanthracene derivative, a fluorenone derivative, a hydrazone derivative,a stilbene derivative, a silazane derivative, an aniline copolymer, andan electroconductive oligomer, particularly a thiophene oligomer. As thehole injecting material, those described above can be used, but aporphyrin compound, an aromatic tertiary amine compound, or astyrylamine compound is preferably used, and an aromatic tertiary aminecompound is more preferably used.

Typical examples of the aromatic tertiary amine compound and styrylaminecompound include N,N,N′,N′-tetraphenyl-4,4′-diaminophenyl,N,N′-diphenyl-N,N′-bis(3-methylphenyl)-[1,1′-biphenyl]-4,4′-diamine(TPD), 2,2-bis(4-di-p-tolylaminophenyl)propane,1,1-bis(4-di-p-tolylaminophenyl)cyclohexane,N,N,N′,N′-tetra-p-tolyl-4,4′-diaminobiphenyl,1,1-bis(4-di-p-tolylaminophenyl)-4-phenylcyclohexane,bis(4-dimethylamino-2-methylphenyl)-phenylmethane,bis(4-di-p-tolylaminophenyl)phenylmethane,N,N′-diphenyl-N,N′-di(4-methoxyphenyl)-4,4′-diaminobiphenyl,N,N,N′,N′-tetraphenyl-4,4′-diaminodiphenylether,4,4′-bis(diphenylamino)quardriphenyl, N,N,N-tri(p-tolyl)amine,4-(di-p-tolylamino)-4′-[4-(di-p-tolylamino)styryl]stilbene,4-N,N-diphenylamino-(2-diphenylvinyl)benzene,3-methoxy-4′-N,N-diphenylaminostilbene, N-phenylcarbazole, compoundsdescribed in U.S. Pat. No. 5,061,569 which have two condensed aromaticrings in the molecule thereof such as4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPD), and compoundsdescribed in Japanese Patent O.P.I. Publication No. 4-308688 such as4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]-triphenylamine (MTDATA)in which three triphenylamine units are bonded in a starburst form.

As the hole injecting material, inorganic compounds such as p-Si andp-SiC are usable. The hole injecting layer can be formed layering thehole injecting material described above according to a known method suchas a vacuum deposition method, a spin coat method, a casting method, anink jet method, and an LB method. The thickness of the hole injectinglayer is not specifically limited, but is ordinarily from 5 nm to 5 μm.The hole injecting layer may be composed of a single layer comprisingone, or two or more of the materials mentioned above, or of plurallayers the composition of which may be the same or different.

The electron injecting layer may be a layer having a function oftransporting electrons injected to the cathode to the light emissionlayer. The material for the electron injecting layer may be selectedfrom known compounds. Examples of the material used in the electroninjecting layer (hereinafter referred to also as electron injectingmaterial) include a nitro-substituted fluorene derivative, adiphenylquinone derivative, a thiopyran dioxide derivative, atetracarboxylic acid anhydride such as naphthalene tetracarboxylic acidanhydride or perylene tetracarboxylic acid anhydride, a carbodiimide, afluolenylidenemethane derivative, an anthraquinodimethane an anthronederivative, and an oxadiazole derivative. Various electron transportingcompounds described in Japanese Patent O.P.I. Publication No. 59-194393is disclosed as compounds for forming a light emission, but it has beenproved that these can be also used as the electron injecting material.Moreover, a thiadiazole derivative which is formed by substituting theoxygen atom in the oxadiazole ring of the foregoing oxadiazolederivative with a sulfur atom, and a quinoxaline derivative having aquinoxaline ring known as an electron withdrawing group are usable asthe electron injecting material. A metal complex of an 8-quinolinolderivative such as tris(8-quinolinolato)aluminum (Alq₃),tris(5,7-dichloro-8-quinolinolato)aluminum,tris(5,7-dibromo-8-quinolinolato)aluminum,tris(2-methyl-8-quinolinolato)aluminum,tris(5-methyl-8-quinolinolato)aluminum, or bis(8-quinolinolato)zinc(Znq₂), and a metal complex formed by replacing the center metal of theforegoing complexes with another metal atom such as In, Mg, Cu, Ca, Sn,Ga or Pb can be used as the electron injecting material. Furthermore, ametal free or metal-containing phthalocyanine, and a derivative thereof,in which the molecular terminal is replaced by a substituent such as analkyl group or a sulfonic acid group, are also preferably used as theelectron injecting material. The distyrylpyrazine derivative exemplifiedas a material for a light emission layer may preferably be employed asthe electron injecting material. An inorganic semiconductor such as n-Siand n-SiC may also be used as the electron injecting material in asimilar way as in the hole injecting layer.

The electron injecting layer can be formed by layering the compoundsdescribed above by a known method such as a vacuum deposition method, aspin coat method, a casting method and an LB method. The thickness ofthe electron injecting layer is not specifically limited, but isordinarily from 5 nm to 5 μm. The electron injecting layer may becomposed of a single layer comprising one or two or more of the electroninjecting material mentioned above, or of plural layers comprising thesame composition or different composition.

A buffering layer (an electrode interface layer) may be provided betweenthe anode and the light emission layer or the hole injecting layer, orbetween the cathode and the light emission layer or the electroninjecting layer.

The buffering layer is a layer provided between the electrode and anorganic layer in order to reduce the driving voltage or to improve oflight emission efficiency. As the buffering layer there are an anodebuffering layer and a cathode buffering layer, which are described indetail in “Electrode Material” page 123, Div. 2 Chapter 2 of “Organic ELelement and its frontier of industrialization” (published by NTSCorporation, Nov. 30, 1998).

The anode buffering layer is described in detail in Japanese PatentO.P.I. Publication Nos. 9-45479, 9-260062, and 8-288069 etc., and itsexamples include a phthalocyanine buffering layer represented by acopper phthalocyanine layer, an oxide buffering layer represented by avanadium oxide layer, an amorphous carbon buffering layer, a polymerbuffering layer employing an electroconductive polymer such aspolyaniline (emeraldine), and polythiophene, etc.

The cathode buffering layer is described in detail in Japanese PatentO.P.I. Publication Nos. 6-325871, 9-17574, and 9-74586, etc., and itsexamples include a metal buffering layer represented by a strontium oraluminum layer, an alkali metal compound buffering layer represented bya lithium fluoride layer, an alkali earth metal compound buffering layerrepresented by a magnesium fluoride layer, and an oxide buffering layerrepresented by an aluminum oxide.

The buffering layer is preferably very thin and has a thickness ofpreferably from 0.1 to 100 nm depending on kinds of the material used.

A layer having another function may be provided if necessary in additionto the fundamental component layers as described above, for example ahole blocking layer may be added as described in Japanese Patent O.P.I.Publication Nos. 11-204258, and 11-204359, and on page 237 of “OrganicEL element and its frontier of industrialization” (published by NTSCorporation, Nov. 30, 1998).

At least one of the cathode buffering layer and anode buffering layermay contain the compound in the invention, and function as a lightemission layer.

As the electrode material for the anode of the organic EL element, ametal, an alloy, or an electroconductive compound each having a highworking function (not less than 4 eV), and mixture thereof arepreferably used. Concrete examples of such an electrode material includea metal such as Au, and a transparent electroconductive material such asCuI, indium tin oxide (ITO), SnO₂, or ZnO.

As the anode, a thin layer of the electrode material described above isformed according to a depositing or sputtering method, in which thelayer may be formed into a desired pattern according tophotolithography, or in which when required precision of the pattern isnot so high (not less than 100 μm), the layer may be formed into adesired pattern through a mask having the pattern. When light is emittedthrough the anode, the transmittance of the anode is preferably 10% ormore, and the sheet resistivity of the anode is preferably not more thanseveral hundred Ω/□. The thickness of the layer is ordinarily within therange of from 10 nm to 1 μm, and preferably from 10 to 200 nm, althoughit may vary due to kinds of materials used.

On the other hand, as the electrode material for the cathode of theorganic EL element, a metal (also referred to as an electron injectingmetal), an alloy, and an electroconductive compound each having a lowworking function (not more than 4 eV), and a mixture thereof is used.Concrete examples of such an electrode material include sodium,sodium-potassium alloy, magnesium, lithium, a magnesium/copper mixture,a magnesium/silver mixture, a magnesium/aluminum mixture,magnesium/indium mixture, an aluminum/aluminum oxide (Al₂O₃) mixture,indium, a lithium/aluminum mixture, and a rare-earth metal. Among them,a mixture of an electron injecting metal and a metal with a workingfunction higher than that of the electron injecting metal, such as amagnesium/silver mixture, a magnesium/aluminum mixture, amagnesium/indium mixture, an aluminum/aluminum oxide (Al₂O₃) mixture ora lithium/aluminum mixture, is suitable from the view point of theelectron injecting ability and resistance to oxidation. The cathode canbe prepared forming a thin layer of such an electrode material accordingto a method such as a deposition or sputtering method. The sheetresistivity as the cathode is preferably not more than several hundredΩ/□, and the thickness of the cathode is ordinarily from 10 nm to 1 μm,and preferably from 50 to 200 nm. It is preferable in increasing thelight emission efficiency that either the anode or the cathode of theorganic EL element is transparent or semi-transparent.

Next, the suitable embodiment of the organic EL element of theinvention, which comprises the structure anode/hole injectinglayer/light emission layer/electron injecting layer/cathode and issealed employing the support of the invention, will be explained.

FIG. 9 shows a sectional view of one embodiment of the EL element of theinvention employing the support of the invention. The EL element has atransparent support 1 and a support 5 (hereinafter referred to also ascounter support 5) opposed to the support 1. The support 1 is thesupport of the invention shown in FIG. 8, which comprises a plasticsheet substrate 100 comprised of a resin such as polyester,polyacrylate, polycarbonate, polysulfone, or polyetherketone, andprovided thereon, a polymer layer and a sealing layer which have beenformed by atmospheric pressure plasma discharge treatment.

An organic EL layer is provided on the support 1, and plural anodes 2are provided in parallel with each other on the layer 101 of the support1 comprising the sheet 100 and provided thereon, a polymer layer 102, asealing layer 101, a polymer layer 102, and a sealing layer 101 in thatorder (laminate layer 7). A thin layer of a desired electrode materialsuch as an anode material is formed by a deposition or sputtering methodso that the thickness of the layer is not more than 1 μm, and preferablywithin the range of from 10 to 200 nm to prepare an anode 2. As theelectrode material for the anode of the organic EL element are used ametal, an alloy or an electroconductive compound each having a highworking function (not less than 4 eV), and a mixture thereof, forexample, a metal such as Au and a transparent electroconductive materialsuch as CuI, indium tin oxide (ITO), indium zinc oxide (IZO), SnO₂ orZnO.

Next, an organic EL layer 3 is formed on the anode 2, wherein althoughnot illustrated, a hole injecting layer, a light emission layer, and anelectron injecting layer are formed on the anode, employing thematerials as described above.

Subsequently, a thin layer of a cathode material selected from thematerials described above is formed by a deposition or sputtering methodto prepare a cathode 4 on the organic EL layer 3. As described above, itis preferable in increasing the light emission efficiency that eitherthe anode or the cathode of the organic EL element be transparent orsemi-transparent.

For formation of each layer of the organic EL element 3, a vacuumdeposition method is preferably used even though a spin coating method,a casting method and a deposition method can be used. The vacuumdeposition method is preferable since a uniform layer can be formed anda pinhole is formed with difficulty. Although conditions of the vacuumdeposition are different due to kinds of materials used or due to anintended crystalline or association structure of the moleculardeposition layer, the vacuum deposition is preferably carried out at aboat temperature of from 50° C. to 450° C., at a vacuum degree of from10⁻⁶ to 10⁻³ Pa, at a deposition speed of from 0.01 to 50 nm/second, andat a substrate temperature of from −50 to 300° C., to form a layerthickness of from 5 nm to 5 μm.

After formation of these layers, a thin layer of a material for cathodeis provided thereon by, for example, a deposition method or sputteringmethod so that the thickness is not more than 1 μm, and preferably from50 to 200 nm, to form a cathode. Thus a desired organic EL element isobtained.

It is preferred that the layers from the hole injecting layer to thecathode are continuously formed under one time of vacuuming to preparethe organic EL element. Further, the organic EL element can be preparedin the reverse order, in which the cathode, the electron injectinglayer, the light emission layer, hole injecting layer, and the anode areformed in that order. Light emission can be observed when a directcurrent with a voltage of from about 5 to 40 V is applied to the thusprepared organic EL element so that the polarity of the anode ispositive and that of the cathode is negative. When the voltage isapplied in the reverse polarity, no current is generated and light isnot emitted at all. When an alternating voltage is applied, light isemitted only when the polarity of the anode is positive and that of thecathode is negative. The shape of the wave of the alternating currentmay be optionally selected.

A protective layer may be provided on the surface of the organic ELlayer 3 including the cathode 4. The inorganic protective layer iscomprised of for example, a dispersion in which SiO₂ is dispersed inCeO₂. The inorganic protective layer may be formed according to asputtering method, an ion plating method, or a deposition method. Thethickness of the inorganic protective layer is 0.1 to 10000 Å, andpreferably 50 to 1000 Å. After the cathode 4 is formed on the organic ELlayer, the inorganic protective layer is successively formed on thecathode under vacuum, which is not taken out from a vacuum chamber, orafter the cathode 4 is formed on the organic EL layer, the resultingmaterial is removed from a vacuum chamber, transported in a nitrogen orinert gas atmosphere, and then the inorganic protective layer is formedon the cathode under vacuum.

The organic EL layer 3 including cathode 4 is covered with a support 5as a counter support, comprising a substrate 100 and a laminate layer 8comprised of a polymer layer 102, a sealing layer 101, a polymer layer102, and a sealing layer 101 provided on the substrate in that order,and sealed.

The sealing is carried out as follows. A sealing agent layer is providedin the frame form on the peripheral portions of the surface of thecounter support 5 (the surface facing the transparent support 1) througha coating method or a transfer method, and the counter support 5 isadhered to the transparent support 1 through the sealing agent layer.Examples of the sealing agent include a heat curable epoxy resin, aphoto curable epoxy resin and an epoxy resin comprising amicro-encapsulated initiator capable of being hardened at ordinarytemperature by application of pressure. In this case, openings (notillustrated) for exhausting air are provided at specific portions of thesealing agent layer to complete the sealing. The openings are closedwith the above epoxy resins or a UV hardenable resin under reducedpressure (at a pressure of preferably not more than 1.33×10⁻² Mpa) orunder a nitrogen gas or inert gas atmosphere.

The above epoxy resin comprises, as a main component, a resin ofbisphenol A type, bisphenol F type, bisphenol AD type, bisphenol S type,xylenol type, phenol novolak type, cresol novolak type, polyfunctionaltype, tetraphenyrolmethane type, polyethylene glycol type, polypropyleneglycol type, hexane diol type, trimethylol propane type, propylene oxidebisphenol A type, hydrogenated bisphenol A type, or their mixture type.When a sealing agent 6 is formed by transfer, a sealing agent ispreferably in the film form.

The counter substrate 100 may be comprised of glass, resin, ceramic,metal, a metal compound, or their composite. The counter substrate ispreferably a substrate with a thickness of not less than 1 μm having awater vapor penetration of not less than 1 g/m²·1 atm·24 hr (at 25° C.)in the test carried out according to JIS Z-0208. Such a substrate may beused as the counter substrate.

In the invention, a material (for example, barium oxide) absorbing orreacting with moisture can be enclosed in the above support.

In the organic EL element as described above, the transparent support 1is adhered to the counter support 5 through a sealing material 6 in theframe form. The organic El element provided on the transparent support 1and cathode 4, etc. can be covered with the counter support 5 and thesealing material 6. Accordingly, the light emission layer can beenclosed at low humidity in the organic El element, and penetration ofmoisture through the support can be restrained, whereby the organic ELdisplay can be obtained in which humidity resistance is improved andgeneration or growth of dark spots is restrained.

FIG. 10 shows a schematic view of another embodiment of the organic ELelement of the invention. The numerical numbers shown in FIG. 10 meanthe same as in FIG. 9.

FIG. 11 shows a schematic view of still another embodiment of theorganic EL element of the invention employing the support of theinvention. The numerical numbers shown in FIG. 11 mean the same as inFIG. 9.

The constitutions of the support and the organic EL element describedabove are the embodiments of the present invention, but the presentinvention is not limited thereto.

EXAMPLES

The present invention will be explained in the following examples, butis not limited thereto.

Example 1

(Preparation of Support A of the Invention)

A methyl methacrylate-vinyl acetate copolymer layer as a polymer layerand an alumina layer as a sealing layer (metal oxide layer) were formedon a 100 μm thick PET (polyethylene terephthalate) film substrate,employing a plasma layer formation apparatus as shown in FIG. 1, so thatfour layers, i.e., a first polymer layer, a first sealing layer(aluminum oxide layer), a second polymer layer, and a second sealinglayer (aluminum oxide layer) were formed on the substrate in that order.Thus, support A was obtained.

Herein, the gas used and power supplied were as follows:

(Preparation of polymer layer) Composition of mixed gas used Inert gas:argon 99% by volume Reactive gas: methyl methacrylate 0.5% by volume(gasified by bubbled with argon at 90° C.) Reactive gas: vinyl acetate0.5% by volume (gasified by bubbled with argon at 60° C.)Power Supplied:

A power of 5 W/cm² with a frequency of 100 kHz was supplied.

(Preparation of sealing layer) Composition of mixed gas used Inert gas:argon 98.75% by volume Reactive gas: oxygen 1.0% by volume Reactive gas:Aluminum isopropoxide 0.25% by volume (gasified by bubbled with argon at160° C.)Power Supplied:

A power of 5 W/cm² with a frequency of 13.56 MHz was supplied.

Example 2

(Preparation of Support B of the Invention)

Support B was obtained in the same manner as in Example 1, except thatsix layers, a first polymer layer, a first sealing layer (aluminum oxidelayer), a second polymer layer, a second sealing layer (aluminum oxidelayer), a third polymer layer, and a third sealing layer (aluminum oxidelayer) were formed on the PET film substrate in that order.

Example 3

(Preparation of Support C of the Invention)

Support C was obtained in the same manner as in Example 1, except thatten layers, a first polymer layer, a first sealing layer (aluminum oxidelayer), a second polymer layer, a second sealing layer (aluminum oxidelayer), a third polymer layer, a third sealing layer (aluminum oxidelayer), a fourth polymer layer, a fourth sealing layer (aluminum oxidelayer), a fifth polymer layer, and a fifth sealing layer (aluminum oxidelayer) were formed on the PET film substrate in that order.

Comparative Example 1

A 1% methyl methacrylate THF solution is spin coated on a PET film (witha thickness of 100 μm) with a size of 100 mm×100 mm, dried, andsubjected to UV lamp exposure to form a polymer layer with a thicknessof 200 nm on the film. Subsequently, the resulting film was fixed in aholder of a vacuum deposition apparatus available on the market, andafter that, pressure in the vacuum chamber of the apparatus was reducedto 2×10⁻⁴ Pa. Then, a sealing layer (an aluminum oxide layer) was vacuumdeposited on the polymer layer to give a thickness of 200 nm.

The process forming two layers described above was repeated two times.Thus, support D (comparative) was obtained.

The process forming two layers described above was repeated three times,employing another PET film. Thus, support E (comparative) was obtained.

The process forming two layers described above was repeated five times,employing another PET film. Thus, support E (comparative) was obtained.

(Peeling Test)

Cross cut test as described in JIS K5400 was carried out. Eleven lineswere cut at an interval of 1 mm in the transverse and longitudinaldirections on the layer surface with a single-edged blade normal to thelayer surface to form one hundred 1 mm square grids. Then, cellophaneadhesive tape available on the market was applied to the grid surface,and the tape, with one edge unattached, was sharply peeled away from thesurface at an angle of 90°. The rate of the area of the peeled layer tothe area of the adhered tape was calculated, and evaluation was carriedout according to the following criteria.

-   A: The rate of the area of the peeled layer to the area of the    adhered tape was from 0% to less than 0.5%.-   B: The rate of the area of the peeled layer to the area of the    adhered tape was from 0.5% to less than 10%.-   C: The rate of the area of the peeled layer to the area of the    adhered tape was not less than 10%.

The results are shown in Table 1.

TABLE 1 Support Peeling test Remarks A A Inventive B A Inventive C AInventive D B Comparative E B Comparative F B Comparative

The inventive samples prepared according to the atmospheric pressureplasma method exhibited good result in the peeling test, compared withthe comparative samples. This is considered to be due to the reason thatthe inventive samples had a more flexible layer as compared to thecomparative samples.

[Preparation of Organic EL Element Employing the Support of theInvention]

FIG. 11 is a sectional view showing the constitution of the organic ELelement prepared. A transparent conductive layer, an IZO (indium zincoxide) layer was formed on the silicon oxide layer of the support A (ofthe invention) prepared above as a transparent support according to a DCmagnetron sputtering method, employing, as a sputtering target, asintering substance comprised of a mixture of indium oxide and zincoxide (In/(In+Zn)=0.80 by mole). Pressure in the vacuum chamber of thesputtering apparatus was reduced to 1×10⁻³ Pa, then a mixed gas of anargon gas and an oxygen gas (argon:oxygen=1000:2.8 by volume) wasintroduced until pressure in the vacuum chamber reached not more than1×10⁻¹ Pa, and the transparent IZO (indium zinc oxide) conductive layerwas formed at a target voltage of 420 V at a support temperature of 60°C. according to the DC magnetron method to obtain a thickness of 250 nm.The resulting IZO layer was subjected to patterning to form an anode,and subjected to ultrasonic washing in isopropyl alcohol, dried with anitrogen gas, and further subjected to UV-ozone cleaning for 5 minutes.

An a-NPD layer with a thickness of 25 nm, a CBP and Ir(ppy)₃co-disposition layer with a thickness of 35 nm (a disposition speedratio of CBP to Ir(ppy)₃ being 100:6), a BC layer with a thickness of 10nm, and an Alq₃ layer with a thickness of 40 nm were formed as anorganic EL layer in that order on the transparent conductive layer andfurther, a lithium fluoride layer with a thickness of 0.5 nm was formedon the Alq₃ layer as cathode buffering layer (not illustrated in detailin FIG. 11). Further, a 100 nm thick cathode of aluminum was formed onthe lithium fluoride layer through a mask pattern.

The support A (as the support 5 of FIG. 11) was superposed on thecathode of the thus obtained laminate under a nitrogen atmosphere. Thusan organic EL element sample OLED-1 was prepared. FIG. 11 shows thestructure in that the transparent electrode and the aluminum cathodewere sealed employing a photo-curable epoxy resin adhesive and a part ofthe transparent electrode and a part of the aluminum cathode can be usedas electrical terminals.

Organic EL element samples OLED-2, 3, 4, 5, and 6 were prepared in thesame manner as in organic EL element sample OLED-1 of Example 1, exceptthat supports B, C, D, E and F were used, respectively, instead ofsupport A.

The light emission layer of each of the above-obtained organic ELelement samples was evaluated as follows.

Nine volts were applied to each sample, and the light emitted portionwas photographed at a factor of 50 power to obtain a first photographicimage of the light emitted portion. Further, each sample was subjectedto folding test in which the sample was folded by an angle of 45°, andreturned to the original position, which was repeated 1000 times, andthen the sample was aged for 100 hours at 50° C. and 80% RH. Then, ninevolts were applied to the resulting sample, and the light emittedportion was photographed at a factor of 50 power to obtain a secondphotographic image of the light emitted portion. The areas of dark spotsin the first and second photographic images were measured, and the darkspot area increase rate defined by the following formula was calculated.Dark spot area increase rate (%)=(Dark spot area in the secondphotographic image−Dark spot area in the first photographicimage)×100/Dark spot area in the first photographic image

The dark spot area increase rate obtained above was evaluated accordingto the following criteria:

-   -   E: The dark spot area increase rate was not less than 20%.    -   D: The dark spot area increase rate was from 15% to less than        20%.    -   C: The dark spot area increase rate was from 10% to less than        15%.    -   B: The dark spot area increase rate was from 5% to less than        10%.    -   A: The dark spot area increase rate was less than 5%.

The results are shown in Table 2.

TABLE 2 Organic EL Support Dark spot area element sample used increaserate Remarks OLED-1 A C Inventive OLED-2 B B Inventive OLED-3 C AInventive OLED-4 D E Comparative OLED-5 E D Comparative OLED-6 F DComparative

As is apparent from Table 2, organic EL element samples OLED-4, 5 and 6(comparative samples), employing comparative supports D, E and F,respectively, exhibited poor results in the folding test. This isconsidered to be due to the reason that cracks, produced in the layer bythe folding test, could not prevent moisture in air from penetratinginto the layer of the samples. Inventive organic EL element samplesemploying inventive supports A, B or C exhibited minimized deteriorationdue to folding test, and provided excellent resistance to folding, whichwere proved to be suitable for flexible displays.

Example 4

A silicon oxide layer was formed on a 100 μm thick polyethyleneterephthalate film, and supports described later were prepared accordingto the procedures as described below. Formation of the silicon oxidelayer according to an atmospheric pressure plasma CVD method was carriedout employing the plasma layer formation apparatus as shown in FIG. 1.

Formation of a silicon oxide layer having a carbon concentration of 3atomic % was carried out employing the gas composition used and powersupplied as shown below (hereinafter referred to as Condition A).

Composition of gas used Inert gas: argon 98.25% by volume Reactive gas1: hydrogen 1.5% by volume Reactive gas 2: tetraethoxysilane vapor 0.25%by volume (gasified by being bubbled with argon)Power Supplied:

A power of 1 W/cm² with a frequency of 13.56 MHz was supplied.

Formation of a silicon oxide layer having a carbon concentration of 0.01atomic % was carried out employing the gas composition used and powersupplied as shown below (hereinafter referred to as Condition B).

Composition of Gas Used

The same gas composition as in Condition A above was used.

Power Supplied:

A power of 10 W/cm² with a frequency of 13.56 MHz was supplied.

The carbon concentration in the silicon oxide layer of each of thesupports described below was determined employing a dynamic secondaryion-mass spectrography (hereinafter referred to also as dynamic SIMS).Regarding the dynamic secondary ion-mass spectrography (dynamic SIMS),JITSUYO HYOMEN BUNSEKI NIJIION SITSURYO BUNSEKI edited by HYOMENKAGAKUKAI (2001, MARUZEN) is referred to. In the invention, dynamic SIMSmeasurement was carried out under conditions as shown below.

-   Spectrometer used: ADEPT 1010 produced by Physical Electronics Co.,    Ltd. or TYPE 6300 secondary ion mass spectrometer

Primary ion used: Cs Primary ion energy: 5.0 KeV Primary ion current:200 nA Area radiated by primary ion: 600 μm square Absorption rate ofsecondary ion: 25% Secondary ion polarity: Negative Secondary ion to bedetected: C⁻

The carbon concentration in the silicon oxide layer is determined underthe conditions as described above. Firstly, based on the carbonconcentration of a standard silicon oxide layer, which is determinedaccording to a Rutherford back scattering spectrography, and intensityof the carbon ion of the standard silicon oxide layer obtained accordingto the dynamic SIMS, relative sensitivity coefficient is obtained. Next,based on the intensity of the carbon ion of a silicon oxide layer of asample to be measured obtained according to the dynamic SIMS and therelative sensitivity coefficient obtained above, the carbonconcentration of the sample is computed. In the invention, the carbonconcentration of the silicon oxide layer is measured through the entirethickness thereof to obtain a depth profile of the carbon concentration.Carbon concentrations are obtained at portions from 15 to 85% of thethickness from the depth profile obtained above, and the average thereofis defined as the carbon concentration in the invention. Thus, thecarbon concentration of the silicon dioxide layer is obtained in termsof atomic % as represented by the following formula:Carbon concentration (atomic %) in the silicon oxide layer=(Number ofcarbon atoms)×100/(Number of all atoms)(Preparation of Support G)

A silicon oxide layer was formed on a 100 μm thick polyethyleneterephthalate film according to an RF sputtering method (frequency:13.56 MHz) employing silicon oxide as a sputtering target to obtain athickness of 880 nm. Thus, comparative support G was obtained.

The carbon concentration of the formed silicon oxide layer was less thanthe lowest limit capable of being detected according to the methoddescribed above.

(Preparation of Support H)

A silicon oxide layer was formed on a 100 μm thick polyethyleneterephthalate film according to an atmospheric pressure plasma CVDmethod employing the condition A described above to obtain a thicknessof 880 nm. Thus, support H was obtained.

(Preparation of Support I)

A silicon oxide layer was formed on a 100 μm thick polyethyleneterephthalate film according to an atmospheric pressure plasma CVDmethod employing the condition B described above to obtain a thicknessof 880 nm. Thus, support I was obtained.

(Preparation of Support J)

A first silicon oxide layer was formed on a 100 μm thick polyethyleneterephthalate film employing the condition A described above to obtain athickness of 220 nm, a second silicon oxide layer was formed on thefirst layer employing the condition B described above to obtain athickness of 220 nm, a third silicon oxide layer was formed on thesecond layer employing the condition A described above to obtain athickness of 220 nm, and a fourth silicon oxide layer was formed on thethird layer employing the condition B described above to obtain athickness of 220 nm. Thus, support J having four silicon oxide layerswas obtained.

(Preparation of Support K)

A fifth silicon oxide layer was formed on the fourth silicon oxide layerof the support J obtained above, employing the condition A, to obtain athickness of 220 nm, and a sixth silicon oxide layer was formed on thefifth silicon oxide layer employing the condition B to obtain athickness of 220 nm. Thus, support K having six silicon oxide layers wasobtained.

Organic EL element samples OLED-7, 8, 9, 10, and 11 were prepared in thesame manner as in organic EL element sample OLED-1 of Example 1, exceptthat supports G, H, I, J and K were used, respectively, instead ofsupport A.

When DC 9 volts are applied to these organic EL element samples, greenlight was emitted. The luminance half-life of light emitted from theorganic EL element samples OLED-8, 9, 10, and 11 was expressed by arelative value (hereinafter referred to also as relative luminancehalf-life) when the luminance half-life of light emitted from the sampleOLED-7 was set at 100. The results are as follows:

-   OLED-8 (123), OLED-9 (142), OLED-10 (425), OLED-11 (641)

The value in the parenthesis represents the relative luminancehalf-life.

As is apparent from the above, organic EL element samples employing thesupports of the invention provided long lifetime.

EFFECTS OF THE INVENTION

The present invention can provide a support with high moisture sealingproperty and without layer exfoliation, which is useful as a display oran electronic device, and an organic electroluminescence element withlong life employing the supports.

1. A support comprising a flexible substrate and provided thereon, oneor two or more polymer layers containing a polymeric compound and one ortwo or more sealing layers containing a metal oxide, a metal nitride ora metal oxide nitride, wherein at least one of the polymer layers andthe sealing layers is formed by a process comprising exciting a reactivegas at a space between opposed electrodes at atmospheric pressure orapproximately atmospheric pressure by electric discharge to be in theplasma state, and exposing the flexible substrate, the polymer layer, orthe sealing layer to the reactive gas in the plasma state, and whereinthe polymeric compound is obtained by polymerization of a monomercomprising a vinyl compound or an acetylene compound, the metal oxide isa compound selected from silicon oxide, titanium oxide, indium oxide,tin oxide, indium tin oxide (ITO), or alumina, the metal nitride is acompound selected from silicon nitride or titanium nitride, the metaloxide nitride is a compound selected from silicon oxide nitride, ortitanium oxide nitride, and the reactive gas is an organometalliccompound or the monomer, and wherein the sealing layer contains carbonin an amount of from 0.2 to 5% by weight.
 2. The support of claim 1,wherein the organometallic compound is an organosilicon compound, anorganotitanium compound, an organotin compound, an organoindiumcompound, an organoaluminum compound, or a composite compound thereof.3. The support of claim 2, wherein the organosilicon compound is acompound represented by formula (1), (2), (3), or (4),

wherein R₂₁, R₂₂, R₂₃, R₂₄, R₂₅ and R₂₆ independently represent ahydrogen atom or a monovalent substituent, and n1 represents a naturalnumber,

wherein R₃₁ and R₃₂ independently represent a hydrogen atom or amonovalent substituent, and n2 represents a natural number, Formula (3)(R₄₁)_(n)Si(R₄₂)_((4−n)) wherein R₄₁ and R₄₂ independently represent ahydrogen atom or a monovalent substituent, and n represents an integerof from 0 to 3,

wherein A represents a single bond or a divalent group, R₅₁, R₅₂, R₅₃,R₅₄, and R₅₅ independently represent a hydrogen atom, a halogen atom, anallyl group, a cycloalkyl group, an alkenyl group, an aryl group, anaromatic heterocyclic group, an amino group or a cyano group, providedthat R₅₁ and R₅₂, or R₅₄ and R₅₅ may combine with each other to form aring.
 4. The support of claim 3, wherein the compound represented byformula (4) is a compound represented by formula (5),

wherein R₆₁, R₆₂, R₆₃, R₆₄, R₆₅, and R₆₆ independently represent ahydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, analkenyl group, an aryl group, or an aromatic heterocyclic group.
 5. Thesupport of claim 1, wherein the content of the metal oxide, the metalnitride and/or the metal oxide nitride in the sealing layer is not lessthan 90% by weight.
 6. The support of claim 1, wherein the sealing layerhas a thickness of from 50 to 2000 nm, and the polymer layer has athickness of from 50 to 2000 nm.